This invention relates generally to sock liner inserts for ice skates or the like.
This invention represents a further development in and is related to the art disclosed in U.S. patent application Ser. No. 316,721, filed Oct. 30, 1981, now U.S. Pat. No. 4,413,430.
For an ice skater, the secure alignment of the foot directly over and along the blade of the skate is integral to performance. When viewed from front or aft, optimum alignment is to have the plane of the blade directly coincide with the sagittal plane of the foot and further directly align with the long axis of the superimposed lower leg. In skating any time the ankle joint and subtalar joint complex is abnormally inverted or everted the alignment must be corrected by direct muscle effort or change in the body position so that the forces related to the thrust of the blade can be readily transmitted from the leg and upper torso as well as forces from the upper torso and leg to the foot to create forward motion. Constant correction and/or the failure to correct the alignment of the ankle and subtalar joint complex relative to the leg reduces the skating efficiency and increases both medial and lateral stress to the ankle. Medial and lateral stress on the ankle and the subtalar joint complex and the required correction associated therewith overwork the muscles employed to correct the alignment which results in reduced efficiency, fatigue, and possible injury. Therefore, the goal is to eliminate lateral stress by maintaining the correct alignment of the subtalar joint in a neutral position relative to the tibia and fibula.
The boot of a skate attempts to capture the ankle in the beneficial alignment described above. In the past, in order for the skate boot to firmly grasp the foot and ankle associated therewith, the boot laces were drawn as tight as possible. This may result in grasping the ankle, but is also causes poor blood circulation in the foot, muscle cramping, fatigue, and general discomfort. In essence, overtighting of the laces is an attempt to make the plantar surface of the foot conform to the topography of the bottom of the skate boot. This overstresses the skeletal structure of the foot and deforms the plantar contour of the foot in an attempt to fit the foot to the boot. Instead, the contours of the skate boot, especially along the interior sole, should be made to conform to an individual's foot and not vice versa. Furthermore, the process of weighting and unweighting changes the contour of the foot as the muscles flex and the stresses are distributed. Prior art devices have attempted to address these problems by providing a sock liner insert constructed of foam to conform to an individual's foot and furnish mild shock absorption qualities.
The following patents represent the state of the art of which applicant is aware insofar so these references appear to be germane to the patent process: U.S. Pat. No. 2,660,814, Ritchey, U.S. Pat. No. 2,680,919, Riggs, U.S. Pat. No. 3,118,153, Hood, U.S. Pat. No. 3,638,336, Silverman, U.S. Pat. No. 3,922,801, Zente, U.S. Pat. No. 3,981,602, Ogden, U.S. Pat. No. 4,017,656, Lasman et al., U.S. Pat. No. 4,055,699, Hsiung, U.S. Pat. No. 4,187,621, Cohen, French Pat. No. 1,240,066, U.K. Pat. No. 465,940.
The above-mentioned references can be characterized as orthopedic appliances for general use, therefore their configuration is likewise general in nature.
By way of contrast, the instant invention is an insert specifically designed for an ice skate and the unique requirements associated therewith. As discussed above, foot alignment relative to the blade and ankle alignment relative to the leg is crucial in determining the relative efficiency and power that can be generated by an ice skater. The foot must directly overlie and remain balanced in relation with the blade, and furthermore the ankle and the subtalar joint complex must remain in a neutral position in relation to the leg. The instant application is distinguished from prior art devices in that a two-stage recess appearing on a bottom surface of the insert causes a controlled deformation of the insert so that in a weighted position the edges of the insert curl up and cup the calcaneal area of the foot and in an unweighted position the memory of the material returns the insert to its original configuration. The controlled deformation of the insert due to the recess aids in the beneficial alignment of the foot relative to the blade and the ankle relative to the leg.